"You must collect things for reasons you don't yet understand."
In the good old days, Kodak used to publish a set of books called Dataguides that had all kinds of useful information. The darkroom dataguides included a "standard" negative and print; the idea was that the user had a practical reference of what a well exposed, well-developed negative and print looked like. He could also use this negative as a standard test to calibrate his own equipment or fine-tune his procedures. (Later Dataguides did not, probably as a cost-saving measure. A shame.)
These standard images featured a pretty caucasian female model; since the model was not identified, somewhere/somehow she acquired the nickname "Shirley," and the negatives (or transparancies) were referred to as Shirleys.
I have seen a couple of explanations as to how the name came to be: one is that it was the name of one of Kodak's preferred models. But I've seen nothing to support it and I consider it apocryphal. I think it's far more likely that someone just came up with the name, it stuck, and spread by word of mouth over the years.
According to Bill C. on photo.net, these came from printer control negatives, which would be used by labs to set up their printers. I believe there would be a Shirley for each film stock (the example at left was shot on Ektacolor), but how many were actually available is anybody's guess.
So there are various and sundry Shirleys out there. How many? I have no idea. So I've created this web page to collect as many as I can find.
Do you have a Shirley that's not here? Please scan it and email it to me and I'll include her!
There's also a relevant discussion of Shirleys on this thread at photo.net